One Strange Prisoners Before offering a picture of these atheist worldviews, I need to say a bit more about what I mean by this word. There is no perfectly settled philosophical definition of the term, and the very idea that we all must inevitably occupy some worldview or another is itself controversial. In that sense, I am begging the question a bit by starting from this assumption. But I hope before I''m done to have gone some way in justifying that approach. As I came to understand it, a proper worldview consists of three related elements: (1) a theory of the underlying nature of reality, (2) a theory of how we ought to act, and (3) a theory of knowledge. I suspect that nearly everyone alive has given some thought to the first two, the subjects of metaphysics and ethics, respectively. Fewer people spend time on the nature of knowledge. Even those familiar with the intellectual subdiscipline that deals with the subject-epistemology-may consider it one of those areas where philosophy drifts from real human concerns into academic navel-gazing.

One of the first things I learned when I started seriously reading modern philosophy, however, was the central position epistemology holds within it. This makes sense when you think about it. Before we can tackle even the most urgent subjects, we need a sound method for separating the true from the false from the senseless. We need to know what form genuine knowledge takes. This becomes clearer if we define metaphysics as knowledge about the nature of reality and ethics as knowledge about proper human action. When we put things this way, however, a problem emerges. Surely the underlying nature of reality ought to determine what form our knowledge about reality takes? There''s an inevitable circularity here: The soundness of an epistemological approach depends on the object under study, but our understanding of the object depends on our approach. The matter gets only more complex when we turn to ethics.

There''s great disagreement on the epistemological issue of whether questions of value can be treated in the same terms as questions of fact. Is knowledge in this area even possible? Is there such a thing as ethical "truth"? Your answers will depend quite a bit on the metaphysical status you accord to ethical values (and to truth itself). The question of value would seem to depend on metaphysics and epistemology both. But there''s also a very real sense in which ethics must take precedence. The decision to pursue certain kinds of knowledge is a decision to act in a particular way, which is to say that it is an ethical decision. Modern sensibilities find something atavistic in the idea that some truths are just too dangerous or destructive to be pursued, but we all take for granted that knowledge of how to make a nuclear bomb, for example, should be kept out of certain hands, and many of us would have no hesitation in stating that humanity as a whole should never have acquired this knowledge in the first place. (It''s insufficient to separate possession of the knowledge from use of that knowledge; the knowledge was sought out-one might say, the knowledge was created-for the purpose of using it.) Ethics can also claim a different sort of precedence.

On a very basic level, it''s the one component of a worldview that we can''t do without. Even the least reflective among us make countless choices every day. We may be entirely unsystematic about them, but our choices inevitably reflect a set of values. As William James notes, our sense of these values might be rather vague, but the choices themselves are necessarily concrete. Certain worldviews make ethical demands of us that are not just impossible to achieve in practice but impossible for us to aspire to achieve. If we can''t recognize a worldview''s "good," we are going to reject that worldview, no matter how theoretically convincing it might be. Conversely, people will believe all sorts of things they can''t otherwise justify, so long as those beliefs make life livable. So it''s difficult to identify one of these elements as the obvious foundation on which the others must rest.

In a compelling worldview, the elements instead reinforce each other. When this happens, we generally don''t think of ourselves as occupying a worldview at all; we are simply living in the world. From inside a coherent and livable worldview, other worldviews seem not just wrong but absurd, while criticisms of a worldview that seem devastating from the outside are viewed from within as utterly missing the point. Yet people do sometimes consciously abandon worldviews, even compelling ones. This is precisely what I did when I gave up on God. I did not feel called from my theistic worldview to some other, better option. The walls of the house where I''d spent all my life had suddenly collapsed, and I needed a new place to live. But it''s incredibly difficult to build a worldview from scratch.

Whenever one attempts to lay foundations, the circularity I''ve been discussing shows itself. At the same time, already existing worldviews can be sometimes unwelcoming. Accepting any one of their elements seems to depend on having already accepted the others. How does one overcome these barriers? This process is the subject of perhaps the most famous metaphor in the history of Western philosophy. In Plato''s Republic , Socrates asks one of his interlocutors (Plato''s older brother, Glaucon) to imagine a group of people trapped all their lives in an underground cave. Far above and behind them, the cave opens out into sunlight, but the light does not reach to where they''re sitting, and they can''t turn to see it, because they are shackled in place, facing the cave''s back wall. Yet they are not in utter darkness. Between them and the opening a fire burns, and between them and the fire is a low wall, "like the screen in front of puppeteers above which they show their puppets.

" People walk back and forth along the wall, carrying statues of humans, animals, and various other objects that project their shadows on the back of the cave. "It''s a strange image you''re describing," Glaucon quite reasonably notes, "and strange prisoners." To which Socrates responds: "They''re like us." In the Platonic view, those of us mired in the ever-flickering, ever-changing world of sense perception are the prisoners in the cave. What we take as reality is only a shadow show. Because our heads are locked in place, we can''t even see our own true selves-enduring souls temporarily passing through these physical bodies-let alone see the real objects whose shadows appear on the wall. Philosophy exists to free people from their bonds so that they might turn away from the shadows, recognize the reality of their situation in the cave, and ultimately leave the cave entirely to stand in the sun of the eternal and unchanging Good. You don''t have to share Plato''s metaphysical rejection of sense perception to recognize the power of his metaphor.

The trope of the cave has had such enormous influence because it can be applied to any movement from the darkness of a mistaken view to the sunlight of the truth. A few points about its picture of conversion have resonated throughout the ages. The first and most basic is that a change in worldview is a conversion-a turning. So long as the prisoners face in this particular way, someone who describes their situation accurately will sound insane. As Socrates has it, language fitted to the shadow world can''t even describe the sunlit aboveground reality. A person who wants to share the experience can only get you facing in the right direction. What''s needed is not the acceptance of some expository theory but the dramatic reorientation of one''s entire life. This turning is not an especially pleasant experience.

Socrates asks Glaucon to imagine someone suddenly freed of these lifelong bonds, able to stand up and face the light. Such a person, Socrates says, would be "pained and dazzled and unable to see the things whose shadows he''d seen before." He might think that he''d been torn away from reality, rather than delivered over to it. Once his eyes adjusted, he would see the fire within the cave and the statues being carried along the wall, and he would recognize that he''d been mistaken about reality. To be truly free, however, he would still need to get out of the cave entirely, to stand in the light of the sun. Leading people to that point is a kind of violence: "If someone dragged him away from there by force, up the rough, steep path, and didn''t let him go until he had dragged him into the sunlight, wouldn''t he be pained and irritated at being treated that way?" Initially, the person dragged into the glare of the sun would be unable to make out anything. He would not see the truth he''d been told to expect, and he might want to return to his old life. But this wouldn''t be possible: His eyes would have adjusted enough to make them useless in the dark cave, even if they couldn''t yet see in the light.

For a time, at least, such a person would be dissociated from any reality at all. Someone who returned to the cave and stumbled around in the darkness would naturally "invite ridicule" among the prisoners. It would be said that he had "returned from his upward journey with his eyesight ruined," and this would be proof that such a journey had not been worthwhile. If this person tried to lead others up where he''d been, the prisoners would "somehow get their hands on him," and they would kill him. The Republic was written about twenty-five years after the death of Socrates, and Plato is clearly putting some retrospective p.